I knew I would get called on my 4x4 exercise habits.... That's fine, I know what you guys are saying and understand it completely... I should have also added that "this is only what I do and seems to work for me. Do this at your own risk"...

I also read about all the much newer 4x4 trucks with a lot less mileage then mine on here that complain that it won't engage or it won't disengage, etc.... When asked how often they put it in 4x4, they say hardly ever or never at all...

Every time my truck hits a gravel road or on the sand at the coast, I pop it in 4hi.... Unfortunately, that just does not happen as much as I'd like.

My owners manual does not forbid the use of 4x4 on pavement, but it does say it's "not recommended" and "doing so could result in difficult disengagement of the transfer case, increased tire wear and decreased fuel economy".

When I do this while stuck in traffic, it's for maybe a mile or two. Always straight line. Rarely above 35 mph. I'm not even getting close to the point of where it will cause increased tire wear or decreased fuel mileage.

I think the mention of it in the manual as 'not recommended' is for leaving it in 4x4 on pavement for extended periods of time, running at normal speeds and taking turns and such that WILL most defiantly put the drive line in a bind.... I guess you can interpret it either way, because in either case, you are adding more to the statement to fit your situation....

Anyway, I appreciate the warnings and I am very conscience of the fact that I'm on pavement. When I'm backing my trailer into it's parking spot at home and I'm in 4lo, I am cranking the wheels lock to lock at times. This IS on a gravel driveway and you can see my tracks where the tires do slip due to the extreme turning I have to do.

I don't know what I'm going to do when that part of the driveway gets paved in the future...... I know I don't want to be in 4lo and cranking the wheels like I have to once it's paved!!

Mitch

 

Yes, you are correct, but we're talking about an '03, not an '04-up.

Also, the IWEs on teh '04-ups are vacuum RELEASE, spring-operated. That way, should the vacuum line spring a leak, the IWEs default to the ENGAGE position thanks to the springs in 'em. It's also one of the reasons you can't flat-tow a new F-series. (i.e. the hubs will engage themselves when vacuum bleeds off)


I can't speak to what you've built, but unless you have worked on some kind of unique transfer cases I've never seen before, when you lock in 4high, you have a 1:1 input to output ratio on both the front and rear driveshafts. You DO get driveline bind-up when off-roading, but because the surface is loose, the tires are able to dig and move the surface as necessary to make the turn. Why do you think it binds up on dry pavement when you make a sharp turn? Doesn't the same thing occur off-road too?

The front and rear driveshafts turn at the same speed coming out of the transfer case. Assuming the gears in the front and rear axles are the same as each other, how could the axles turn at different speeds?

Lets look at it another way.... Let's say, for a moment, that your theory is correct. Lets say that the front driveshaft turned 10% faster than the rear driveshaft. In order for the truck to drive straight ahead down the road, the front wheels have to roll the same distance as the rears. Now, in order for that to happen with a front driveshaft turning 10% faster than the rear, the front axle final drive ratio would have to be 10% lower (numerically higher) than the rear. Otherwise, the front wheels would want to turn farther than the rears, no? So, if you had 3.55 rear gears, you'd need to be running 3.91 front gears to keep the front wheels turning at the same speed as the rears.

The only exception I've ever heard of is in mud drag-race trucks. They'll run a permanently locked transfer case with a different gear ratio in the front and rear axles. The fronts will run taller (i.e. numerically lower) gear ratios to keep the front wheels spinning on top of the mud and help provide better directional control. They can get away with it because, on the surfaces they run on, the tires can slip. Throw a set of street tires on one and drop it in a parking lot, and it's not going to go anywhere without a lot of tire squealing and howling.

-Joe

 

That's easy!!

1) Pop the hood.
2) Unplug the 'engage' solenoid for the center-axle disconnect (passenger-side firewall behind the battery, two small two-wire plugs side by side. I forget which is the engage side, but you can unplug them both if you're not sure...)
3) Engage low range.
4) Back the trailer. You will essentially be in 2wd low range.

Essentially, you're fooling the system into maintaining the broken passenger-side front axle shaft it normally has in 2wd. That means that even though the front driveshaft is still locked to the rear via the transfer case, the front axle cannot transmit any power, and acts like an open diff with a broken axle shaft because, well, it is.

 

Thanks Joe!

I've heard of being able to do that. That might be what I will have to resort to!

It would be cool if there was some way to design some sort of valve setup that all you had to do was turn a couple of valves spliced into the vacuum lines under the hood... Probably not enough room for something like that, but an interesting thought..... Humm.....

Mitch

 

I don't throw it in 4hi until I can no longer move forward in 2wd. I would never throw it in 4lo until I couldn't move any further in 4hi or I had the need for the torque to tow something in 4wd. The times when I need to 'excercise' the 4x4, I can always find dirt or grass to drive back and fourth for a couple minutes. I can't see any benefit to driving on wet pavement at 60 mph in 4wd. I may have thrown it into 4lo once for a minute on a slippery surface just to see how it felt. Do yourself a favor. Open your owner's manual or find one for your truck and look at the instructions for appropriate 4x4 use before you break something.

 

Actually, all you would need to do is wire up a DPDT on-on switch into the two wires that ground those two solenoids to the GEM. Accessing them is a piece of cake as they're right there in the open, and running two wires into the cab is hardly a chore. Then, with the switch in position 1, everything would work normally. In position two, it would force the disconnect to stay disconnected.

I drew up a quick sketch of the wiring to do that.... I'll try and scan it in and post it from work in the AM.

By the way, we should probably start a new thread for this one.... Title it 2WD LOW Range....

Sorry for the thread hijacking....

-Joe

 

Awesome idea on both counts Joe!! Looking forward to it!

 

The only time I ever used 4wd low with 1st gear was while I was rockcrawling and that is about it. It really keeps the engine running slow but my advice would be not to use it over 25 mph, that is why you have 4wd high. Anyway, even 4wd low did not get me out of the mud.........damn

 

i must have been thinking the wrong thing this whole time. i always thought that both the front and rear ends spun exactly the same speed, since they are suppossed to have the same (or close) gear ratios. also, assuming that the front end has an open differential, it wouldn't really matter as to wether or not the driveshafts are spinning at the same rate and that the front has to travel a greater distance while turning, because the open differential would allow both wheels to turn at the rate they need to. but i guess im wrong, i learn something new every day.

 

4 low seems to work great for me when I am creeping through mud. It increases RPM's which means....well i dont know exactly what it means. But it works.

Has anyone accidentally driven in 4hi on dry pavement, and when you turn it feels like you are turning on sticky asphalt?

 

I did that trying to get off the jack at discount. The pavement was wet so with the weight of the front end, the back could not pull and the tires were slipping. So 4wd hi but you could feel that the truck did not like that very much. The new trucks are not any better than the old one when it comes down to 4wd hi and dry pavement.

4wd is definitly for off-road or poor grip conditions.

 

I've only used the 4Low on the truck 2ice since i've got the truck. First off, when i test drove the truck i put it in 4 Low and drove it 2 feet to make sure there were no clunking noises. Done on the side of the road in lots of dirt. So no damage was done.

The other was this weekend when my boat got stuck, and i mean STUCK in a lake. So, i have used the 4 Hi many times, backing a trailer up, snow, and driving to and from the polebarn to the house, just to keep the axles all lubed up. Have i needed it for any of the uses in Hi? Probably not, but it makes a 50 mile trip in 4-5 inches of fresh snow much safter, and more relaxing. Just can't drive like a maniac and you can keep it in 2. But i love downshifting to slow down in snow. Watch the guy behind you lose control when he locks up on the breaks for riding your ***.

 

How did you do that???

I have heard some stories but that one is funny. How did you get that boat stuck?